From the point of view of the customer, it is essential to have reliable information on the benefits and costs received. The payback time should be known in different situations and uncertain investments are not the means to accepted. Related to energy efficiency, it is often assumed that measuring is the only correct and accurate way to make energy efficiency decisions. If so, then it should be considered how accurate the results should be?
If the savings are estimated at +/- 10% and the cost is +/- 10%, then the uncertainty of the repayment period is approximately +/- 14%. However, it is very rarely possible to predict the costs. Lowering the uncertainty of savings by +/- 3% improves the uncertainty of the repayment period by approx. +/- 11%. On the other hand, savings of +/- 7% +/- 12% are achieved in uncertainty. So the pursuit of better accuracy is a waste of money. However, the real uncertainties of savings are much larger. It is certainly a good idea to know where the uncertainty of energy savings is due.
According to the studies the optimization of the energy consumption of individual equipment and components often leads to bad mistakes in the energy balance. This error is also called suboptimization. This is usually the result of energy-based purchases of energy-based appliances, individual component reviews, and CAD-based software. Reliability of results problems arise whenever all energy fractions and interaction between energy streams are ignored. Ignoring the heating and cooling cycles distorts the results as well. This often happens when the calculation becomes too complicated or the goal is to supply only certain devices.
Are the measurements anyway the only correct way or whether they want to avoid using other methods? The benefits of continuous measurements are often low, so its enrichment can be overlooked. Everything is virtually impossible to measure. The design of power plants, paper machines, pulp mills, etc., and their production and quality optimization are based on modeling. Why could not it also work in energy efficiency?
Good modeling of energy balance results in better accuracy and reliability in studies. This is because of their ability to deal with complicated interactions. Its calculations can take into account all the energy bills also those that can not be measured. The calculations take into account all heating and operating cycles correctly. Best of them can be optimization and scenarios for the future, including monitoring of energy management measures and results. According to several international comparative studies, modeling also results in the same accuracy and measurement as individual consumption.